Where do you think the poem's speaker was going in the poem "Stopping by Woods on a Snowy Evening?"
I have always imagined that the speaker of the poem, whom I take to be Robert Frost himself, has driven into a little town for provisions, and possibly for a few Christmas presents, and is on his way back to the farm where he lives when he stops to look at a beautiful scene. It is wintertime. He wouldn't have gone on a trip in a horse-drawn sleigh if it wasn't necessary. The fact that the little horse shakes it head and makes its harness-bells ring suggests that it wants to get home to a warm stable and something to eat. If the speaker were on his way to town rather than on his way back home, the horse would not be anxious to proceed. But everybody who knows anything about horses knows that they show more vitality when they are heading back to the barn. The horse knows very well where they are going and wants to get there, especially because of the cold and the falling snow. It is a "little horse" and a heavy sleigh. It would like to get unhitched from that thing it has been pulling for miles and miles. The speaker might have sat there a little while longer if the horse hadn't shown its impatience. I picture the sleigh being loaded with packages. The speaker wouldn't take a trip into town just to pick up one or two items. He must have bought all the provisions he and his family would need for a week or two. There is an implied contrast, I believe, between the very practical purpose of the trip to and from town and the sudden impulse to stop for no practical purpose whatever but just to enjoy the beauty of the isolated scene. We all need to stop sometimes and just take in the beauty of nature, assuming we have any access to nature where we live. There is a need in most humans for some contact with natural beauty, but it's easy to repress that need when we are preoccupied with "getting and spending," as Wordsworth says in his well-known sonnet. I think we like Frost's poem because we identify with the speaker. We understand how he would just like to take some time out and feel that he himself is a part of nature.
Perhaps the poem is a metaphor for life's obligations that are in conflict with the enjoyment and appreciation of nature. The poet stops to admire the pristine woods and the beauty of the natural spot in which he stops; however, when his horse shakes his bells, he is reminded of his obligations, forcibly reminded that he "has miles to go" before he can rest.
It's impossible to know precisely where the speaker is heading. We gather from his reference to "promises to keep" that he is running some kind of errand. We cannot even be sure if he is heading out to complete the errand or if he previously completed the errand and is now on his way home. We know that he must not be too far of a distance from his home--he believes he knows who owns the woods where he has stopped and that owner's house is in town. Regardless, the errand is little more than a context for the poem's message that the beauty of the natural world is worth stopping for and contemplating despite the fact that we all have "miles to go before we sleep."
There are good arguments that the poem relates to death, and more specifically, suicide. The poem deliberately correlates darkness with beauty ("the woods are lovely, dark and deep.") Also, the poem mentions twice that the traveler has stopped on his journey. He has stopped at night, on "the darkest evening of the year", far from civilization, and in the middle of a snowfall. As he stands there, contemplating lovely darkness, even his horse tries to stir him, to “ask if there is some mistake”, conveying that the situation is, perhaps, not as it should be. It would not be a stretch to infer that the horse has a real and appreciable understanding of the danger that stopping in the woods on a cold night represents. Finally, the last lines tend to indicate that the traveler wants to "sleep", and his obligations stand between him and the ability to do so. It could be argued from the repetition of the last line that the traveler is fighting an internal war between his desire to lay down his worldly obligations, his "promises to keep", and his sense of duty that urges him to go those last miles before he does so. These last two lines sound, in this context, at least, like the mantra a person with a distasteful task before them repeats as they try to motivate themself do push through it.
So based on these arguments, I would suggest that the traveler in the poem is not, in fact, going to a physical place, but rather struggling to move through a sort of world-weariness that lulls him to simply let go. Please note that the poem is specifically and intentionally silent on the matter of forward motion. We get the impression that the traveler has not moved at all through the course of the poem. We do not know even, where he has come from or how he came to be where he is, and so the feeling is one of cold, deathly stillness.